Lesson Plan

Perimeter and Area of Triangles in the Cartesian Plane

Curated and Reviewed by Lesson Planet

Pupils figure out how to be resourceful when tasked with finding the area of a triangle knowing nothing but its endpoints. Beginning by exploring and decomposing a triangle, learners find the perimeter and area of a triangle. They then work with the coordinates of the vertices of the triangle to create a formula for the area of the triangle. 

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CCSS: Designed
Additional Tags
Instructional Ideas
  • Use graphing white boards as scholars explore the patterns in the triangles
Classroom Considerations
  • Provide graph paper to individuals for them to use as they explore the examples in the lesson
  • Uses the distance formula to determine lengths of sides of triangles on the coordinate plane
  • The ninth lesson in a series of 15
Pros
  • Provides teacher notes and questioning suggestions throughout the lesson
  • Includes answer keys for the lesson, practice problem set, and opening and closing activities
Cons
  • Quickly moves to abstract formulas; learners can find the indicated measures without using the formulas
Common Core